package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.dto.Result;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Follow;
import com.hmdp.mapper.FollowMapper;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * <p>
 * 服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class FollowServiceImpl extends ServiceImpl<FollowMapper, Follow> implements IFollowService {
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private IUserService userService;

    @Override
    public Result follow(Long followUserId, Boolean isFollow) {
        //获取当前登录的用户
        Long userId = UserHolder.getUser().getId();
        String key = "follows:" + userId;
        //判断到底是关注了还是取关
        if (isFollow) {
            //关注，新增follow关联表
            Follow follow = new Follow();
            follow.setFollowUserId(followUserId);
            follow.setUserId(userId);
            boolean isSave = save(follow);
            if (isSave) {
                //把关注目标用户的id放入redis集合 sadd userId followUserId

                stringRedisTemplate.opsForSet().add(key, followUserId.toString());
            }
        } else {
            //取关，删除follow关联表 delete from tb_follow where user_id = ? and follow_userId =?
            boolean isRemove = remove(new QueryWrapper<Follow>().lambda()
                    .eq(Follow::getUserId, userId).eq(Follow::getFollowUserId, followUserId));
            //移除redis中关注的的用户id
            if (isRemove) {
                stringRedisTemplate.opsForSet().remove(key, followUserId.toString());
            }
        }
        return Result.ok();
    }

    @Override
    public Result isFollow(Long followUserId) {
        //获取当前登录的用户
        Long userId = UserHolder.getUser().getId();
        //查询是否关注，根据
        Integer count = lambdaQuery()
                .eq(Follow::getUserId, userId).eq(Follow::getFollowUserId, followUserId).count();
        return Result.ok(count > 0);
    }

    @Override
    public Result followCommons(Long id) {
        //获取当前登录用户，再去求交集  //根据redis的set集合，求共同关注
        Long userId = UserHolder.getUser().getId();
        String key = "follows:" + userId;
        String key2 = "follows:" + id;
        Set<String> idSet = stringRedisTemplate.opsForSet().intersect(key, key2);
        if (idSet == null || idSet.isEmpty()) {
            return Result.ok(Collections.emptyList());
        }
        //解析id，查询用户
        List<Long> ids = idSet.stream().map(Long::valueOf).collect(Collectors.toList());
        List<UserDTO> userDTOS = userService.listByIds(ids).stream()
                .map(user ->
                        BeanUtil.copyProperties(user, UserDTO.class)
                ).collect(Collectors.toList());

        return Result.ok(userDTOS);
    }
}
